The use of bridging beams to reinstate poles used by utilities for carrying communications lines, electric power lines and the like has become an effective means for extending the lifetime of damaged, rotted or weakened poles. The term reinstatement as used herein is also to be understood as including reinforcement. Whilst bridging beams have specifically been used to reinstate poles used by utilities, it is to be appreciated that this technique has application to other forms of poles including pylons, stumps, flagpoles, warning posts and the like and as such, the invention also has application in these alternative situations.
Bridging beams have particular application to wooden poles. It is well known that a wooden pole is most vulnerable to rot, decay or similar degradation at about ground level including the area from slightly above to slightly below the ground line of the standing poles. This is the area in which rot generally begins and as the decay spreads, the pole is weakened. If a utility pole should fail, there may be serious disruption to telecommunications and/or power supply. Further, the sudden failure of a pole is a risk which linesman working on such poles face regularly. In addition to the risks of a faulty pole falling and bringing down not only the lines but also the linesman with it, there are risks to passersby and neighbouring buildings or other structures. Similar dangers and inconvenience may result from the failure of poles used in other applications.
Thus, the reinstatement of damaged poles is an important consideration. However, it can be difficult to properly identify damage to a pole. Accordingly it may sometimes be necessary or advisable to provide added strength to a sound pole. The terms reinstate and reinstatement are accordingly used herein to refer to the addition of strength to a pole irrespective of whether the pole has been previously damaged and/or weakened in any way.
Typically, a pole may be reinstated by securing a pre-assembled structurally strong bridging beam to the surface of a pole over the region where it is rotted or weakened. The bridging beam may be securely attached by drilling holes diametrically through the pole and securing the bridging beam to the pole by bolts extending completely through the material of the pole. Where a pole is particularly weakened, two or even more bridging beams may be applied in this fashion.
In another approach the bridging beam simply comprises a very strong steel sleeve which is applied against the side of a pole and secured by means of strapping, bolts, screws, ferrules, backing plates or combinations of these. Of course, in order to provide adequate strength, a simple sleeve forming a bridging beam needs to be manufactured from a heavy gauge steel.
Whilst the various approaches which have been tried for reinstating poles have been used with a measure of success, they generally suffer from one or more disadvantages depending upon the circumstances of use and the economics of use of particular styles of bridging beams in different situations.
There is always room for alternative constructions which may be optimal for a range of situations in which the current styles of bridging beams suffer from disadvantages. Thus, the invention seeks to provide an alternative method for installing bridging beams and bridging beam constructions which may be used for operation of such methods.